code: def _get_reference_map():
      """
      Sphinx computes references for type annotations using fully-qualified classnames,
      so references in undocumented modules (even if the referenced object is exposed via
      a different module from the one it's defined in) are considered invalid by Sphinx.
  
      Example:
      ```
      def start_run(...) -> ActiveRun:
          # ActiveRun is defined in `mlflow/tracking/fluent.py`
          ...
      ```
  
      For this code, Sphinx tries to create a link for `ActiveRun` using
      `mlflow.tracking.fluent.ActiveRun` as a reference target, but the module
      `mlflow.tracking.fluent` is undocumented, so Sphinx raises this warning:
      `WARNING: py:class reference target not found: mlflow.tracking.fluent.ActiveRun`.
      As a workaround, replace `mlflow.tracking.fluent.ActiveRun` with `mlflow.ActiveRun`.
      """
      ref_map = {
          # < Invalid reference >: < valid reference >
          "mlflow.tracking.fluent.ActiveRun": "mlflow.ActiveRun",
          "mlflow.store.entities.paged_list.PagedList": "mlflow.store.entities.PagedList",
      }
  
      # Tracking entities
      for entity_name in mlflow.entities.__all__:
          entity_cls = getattr(mlflow.entities, entity_name)
          invalid_ref = entity_cls.__module__ + "." + entity_name
          valid_ref = "mlflow.entities.{}".format(entity_name)
          ref_map[invalid_ref] = valid_ref
  
      # Model registry entities
      for entity_name in mlflow.entities.model_registry.__all__:
          entity_cls = getattr(
              mlflow.entities.model_registry, entity_name
          )
          invalid_ref = entity_cls.__module__ + "." + entity_name
          valid_ref = "mlflow.entities.model_registry.{}".format(
              entity_name
          )
          ref_map[invalid_ref] = valid_ref
  
      return ref_map
  
file_path: mlflow/docs/source/conf.py
imports: import sys
  import os
  from docutils.nodes import Text
  from sphinx.addnodes import pending_xref
  import mlflow
  import languagesections
  import mlflow.version
label_desc: Use image node_id 1 for calling a global function with example usage: _get_reference_map() and returns: ref_map